Machines such as, for example, dozers, motor graders, wheel loaders, and other types of heavy equipment are used to perform a variety of tasks. Some of these tasks require very precise and accurate control over operation of the machine that is difficult for an operator to provide. Other tasks requiring removal of large amounts of material can be difficult for an unskilled operator to achieve efficiently. Poor performance and low efficiency can be costly to a machine owner. Because of these factors, the completion of some tasks by a completely operator-controlled machine can be expensive, labor intensive, time consuming, and inefficient.
One method of improving the operation of a machine under such conditions is described in U.S. Pat. No. 5,005,652 (the '652 patent) issued to Johnson on Apr. 9, 1991. The '652 patent describes a track laying vehicle carrying a bulldozer blade, which can be raised or lowered by a pair of hydraulic rams. The rams are under the control of a control system carried on the vehicle. The blade carries an upwardly extending mast having a laser beam detector for receiving signals emitted by a laser-formed reference plane. In use, the track laying vehicle can be driven forward while the signal from the laser-formed reference plane is received by the detector. The detector determines whether a locus of the detector, the blade, and hence the profile of the work surface being produced are deviating from a required datum. Upon detection of a deviation, the control system provides hydraulic control of the rams such that the detector, blade, and the cut surface are returned to the correct elevation parallel to the reference plane.
To produce a non-planar surface, a distance wheel may be mounted to the tracked vehicle of the '652 patent to give a distance measurement from a starting point. During operation, the blade can be traversed in a direction generally parallel to the reference plane while varying the distance of the blade from the reference plane in accordance with instructions from the control system. The instructions are issued by the control system in accordance with the distance measurement transmitted to it by the distance wheel and a desired contour.
Although the track laying vehicle of the '652 patent may be capable of producing accurate surface contours during an excavation process, it may not consider efficiency when doing so. In particular, the control system associated with the track laying vehicle does not consider an amount of material being moved during each excavation pass, a condition of the material, a capacity of the track laying vehicle to move the material, or a resulting intermediate contour (e.g., the contour of the surface after a first excavation pass, but prior to a final excavation pass). Instead, the control system of the '652 patent is only capable of blindly following a predefined contour map and, typically, is only used for final grading operations. For this reason, the track laying vehicle of the '652 patent may be inefficient at producing the desired surface contour and at moving large amounts of material that require multiple excavation passes.
The disclosed system is directed to overcoming one or more of the problems set forth above.